Drug used in dementia carries kidney risk

TORONTO - A class of drugs sometimes used to control symptoms of dementia appears to increase the risk of acute kidney injury in people who take it, a new study suggests.

The work looks at what are called atypical antipsychotic drugs, which are not recommended for dementia but which nonetheless are often prescribed for people suffering from it.

A number of studies have questioned use of the drugs in this population of patients, for a variety of concerns. Health Canada, the U.S. Food and Drug Administration and Britain's drug regulatory body have all recommended that the drug not be used to control symptoms of dementia.

Despite that, the drugs — Seroquel (quetiapine), Risperdal (risperidone) and others — are prescribed to control symptoms such as aggression and agitation that are sometimes seen in dementia patients.

But there have been case reports of kidney ailments in older adults who start taking the drugs. So researchers from Lawson Health Sciences Centre in London, Ont., and the Institute for Clinical Evaluative Sciences in Toronto set out to see if there was a link between use of the drugs in this population and kidney problems.

They studied the health records of nearly 100,000 adults 65 years of age and older from Ontario who were newly prescribed one of these drugs during the period from June 2003 to December 2011. They then compared those records to nearly 100,000 people of similar ages and health status who did not take one of those medications.

The rate of acute kidney injury was essentially doubled in the group taking the drugs, said Dr. Amit Garg, a kidney specialist at Lawson Health Sciences Centre who is also a scientist at ICES.

When the researchers looked at how many people died in the first three months of taking the drug, they found 6,666 people taking the drugs died compared to 2,985 in the control group.

Garg said it is important to note these findings only pertain to older adults taking the drug for dementia. The researchers did not study their use in people who are prescribed the drugs for mental health conditions.

"They generally would be less at risk of side-effects anyway and they shouldn't be alarmed by these data," he said.

Garg said the findings suggest doctors should be cautious about using these drugs in this patient population, turning to them as a drug of last resort. "If there are other options that are available, really explore those."

If using one of these drugs appears to be the best option for a dementia patient, the doctor should monitor the patient for signs of kidney problems.

And if someone with dementia shows up needing care for kidney ailments, doctors should ask whether the patient is taking an atypical antipsychotic. Garg said withdrawing the treatment can sometimes ameliorate the condition, though he warned that patients should not stop taking these drugs without first consulting a doctor.